The combination of rCBV values derived from T1-perfusion MRI and SWI derived ITSS scores improves the diagnostic accuracy for discrimination of grade III from grade IV gliomas.

OBJECTIVEMultiple-site neural tube defects (MNTDs) are very uncommon, with the predominant number of cases being reported in developing countries. The classic theory of neural tube closure fails to explain the occurrence of these defects. Multisite closure theory, first proposed in 1995, explains most of the occurrences with a few modifications specific to a few defects. In this paper, the authors endeavor to explain all the defects, along with their genetic and embryological bases, and to review the available literature and discuss their own experience in the management of these complex cases.METHODSThe authors retrospectively reviewed the data of all the patients treated surgically for MNTDs over that past 14 years. All possible demographic data, clinical details, and radiological imaging data were reviewed. In addition, surgical parameters, complications, and status at follow-up of more than 12 months were evaluated. All previously reported cases of MNTD were analyzed, and comparisons with the present series were made.RESULTSA total of 3 major series (including the present one) on MNTDs have been from India. A total of 57 such cases (including those of the present series) have been reported in the available literature. While previous series reported a higher incidence of spinal defects, the present series had a higher rate of cephalic defects (55%). Among the reported cases, insertion of a ventriculoperitoneal shunt was necessary in 12 (26%), and only 4 patients were operated on in 2 stages. Neurological status at presentation dictated outcome.CONCLUSIONSMNTDs are extremely rare, and their embryogenesis is different from that of single neural tube defects. Simultaneous repair of 2 or even 3 defects is possible in a single-stage surgery. The requirement of a shunt is uncommon, and complications following surgery are rare. Folic acid supplementation may reduce the incidence of defects.

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Introduction:Intracranial schwannomas arising from non-trigeminal and non-vestibular sources are extremely rare constituting <0.8% of all schwannomas. In this article, we have analyzed our experience in the management of these rare tumors over a 10-year period.Material and Methods:There were a total of 16 cases, with 11 of them undergoing microsurgical resection and 5 undergoing stereotactic radiosurgery (SRS).Results:There were no fresh neurological deficit in any of these patients and two patients underwent postoperative SRS for residual tumor. One patient died due to postoperative septicemia.Conclusion:Knowledge of these lesions along with their clinicoradiological profile is essential to maintain a high index of suspicion and understand the nuances of treatment.

Background/Aims: Perfusion magnetic resonance imaging (MRI) is useful for preoperative assessment of brain tumors. Dynamic susceptibility contrast perfusion MRI is commonly used for evaluation of brain tumors. Dynamic contrast-enhanced (DCE) MRI is an alternative method that has mainly been used in adult brain tumors. In this preliminary study, we report our initial experience with the DCE perfusion MRI in pediatric brain tumors. Methods: Sixty-four newly diagnosed pediatric brain tumor patients underwent DCE perfusion MRI on a 3-T scanner. Hemodynamic and kinetic parametric maps were generated and the regions with the highest values were measured on each map. Statistical differences were sought to differentiate between low-grade tumors, high-grade tumors, and medulloblastomas. The perfusion metrics of common posterior fossa tumors were also compared. Results: Relative corrected cerebral blood volume (rCBV) and fractional plasma volume measures differed significantly between high- and low-grade tumors (p < 0.05). High-grade tumors could be differentiated from low-grade tumors, with an rCBV cutoff value of 2.41 and 88.6% sensitivity and 65% specificity. There was no significant difference in K^trans, K_ep, V_e, or λ^tr between these 2 groups of tumors. rCBV, relative quantification of the cerebral blood flow, and permeability indices were found to be significantly different in various posterior fossa tumors, i.e., pilocytic astrocytoma, ependymoma, and medulloblastoma (p < 0.05). Conclusion: DCE-derived perfusion metrics are useful in differentiating high-grade tumors from low-grade ones and discriminating among various posterior fossa tumors in the pediatric age group.

These are challenging tumours to treat and are associated with sizable morbidity and mortality. On statistical analysis, we found that if the tumour has a size of 3-5 cm and petroclival in location with no sphenoid extension and the lesion is homogenous on T2-weighted images, then there was a trend towards gross total resection and favourable outcome.

Objective To describe the magnetic resonance imaging characteristics of supratentorial ependymomas. Methods The magnetic resonance imaging and computed tomography imaging characteristics of 49 cases of supratentorial ependymomas were analyzed retrospectively. The location, size, degree of perilesional edema, gross appearance, computed tomography attenuation characteristics, T1 and T2 signal intensity characteristics, degree of diffusion restriction, presence of calcification, and hemorrhage were documented for each lesion. The intratumoral susceptibility scores (ITSS), apparent diffusion coefficient (ADC) values, relative cerebral blood volume, and choline/N-acetyl aspartate ratios were documented where available. Results The frontal lobe was the most common location with a mean size of 6.37 × 4.8 cm. Severe perilesional edema was evident in 30%. Heterogenous, solid-cystic appearance was present in 96% lesions, with 95% of extraventricular lesions extending from pial surface to the ventricular margin. Calcification was seen in 55% of cases. The ITSS was 3 in 85.7% of lesions. The mean ADC value calculated was 600 × 10−6 mm2/s. The mean relative cerebral blood volume on dynamic susceptibility contrast perfusion was 4.83. The mean choline/N-acetyl aspartate ratio was 5.87. Leptomeningeal dissemination was demonstrable in 5 lesions. Four lesions were abutting the dura with frank dural invasion in one. One patient presented with disseminated disease without evidence of a primary lesion. Conclusions A large lesion with relatively well-defined margins, heterogeneous solid cystic appearance, extending from the pial surface to the ventricular margin, presence of calcification, and ADC values approaching those of white matter should raise a suspicion of supratentorial ependymoma. High ITSS, MR perfusion parameters, and magnetic resonance spectroscopy characteristics are similar to those of other high-grade gliomas.

Objective To assess the inter-technique agreement of relative cerebral blood volume (rCBV) measurements obtained using T1- and T2*-perfusion MRI on 3T scanner in glioma patients. Methods A total of 49 adult patients with gliomas underwent both on T1- and T2*-perfusion in the same scanning session, and rCBV maps were estimated using both methods. For the quantitative analysis; Two independent observers recorded the rCBV values from the tumor as well as contralateral brain tissue from both T1- and T2*-perfusion. Inter-observer and inter-technique rCBV measurement agreement were determined by using 95% Bland-Altman limits of agreement and intra-class correlation coefficient (ICC) statistics. Results Qualitative analysis of the conventional and perfusion images showed that 16/49 (32.65%) tumors showed high susceptibility, and in these patients T2*-perfusion maps were suboptimal. Bland-Altman plots revealed an agreement between two independent observers recorded rCBV values for both T1- and T2*-perfusion. The ICC demonstrated strong agreement between rCBV values recorded by two observers for both T2* (ICC = 0.96, p = 0.040) and T1 (ICC = 0.97, p = 0.026) perfusion and similarly, good agreement was noted between rCBV estimated using two methods (ICC = 0.74, P<0.001). ROC analysis showed that rCBV estimated using T1- and T2*-perfusion methods were able to discriminate between grade-III and grade-IV tumors with AUC of 0.723 and 0.767 respectively. Comparison of AUC values of two ROC curves did not show any significant difference. Conclusions In the current study, T1- and T2*-perfusion showed similar diagnostic performance for discrimination of grade III and grade IV gliomas; however, T1-perfusion was found to be better for the evaluation of tumors with intratumoral hemorrhage, postoperative recurrent tumors, and lesions near skull base. We conclude that T1-perfusion MRI with a single dose of contrast could be used as an alternative to T2*-perfusion to overcome the issues associated with this technique in brain tumors for reliable perfusion quantification.